Here is the second part of this tool which has to do with alpha channel estimation which involves not only plucking the objects out, but also making sure that the object boundaries are realistic in the sense that they gradually merge into one region on one side and into the other region on the other side. In this case the leg of the doll should not be plucked so that the boundaries, it is cut the boundary indeed. What you want is some green of the grass in the boundary, near the boundary of the doll's leg and some colour of the dolls legs should spill over into the green grass. And that will give it more realistic look.

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